The returning source element will indicate if the phone number matched a specific database and may determine if the device used is a mobile phone or a landline phone.

One or more phone source codes can be supplied in the GET request, in order to narrow the search to specific databases.

Code	Name	Description
A	Mobile and Landline Authoritative Data	Authoritative Data Source database. Contains 800 million mobile and landline data from Caller Id sources. Estimated connection rate: 95%. Updated monthly.
D	Landline Directory Assistance	Directory Assistance data collected daily from regional Bell phone companies and other sources. Approximately 90 million residential listings and 20 million business listings. Estimated connection rate: 90%. Updated daily.
P	Landline Premium	Premium Phone. Contains approximately 200 million residential listings and 20 million business listings compiled from phone companies and marketing data sources. Estimated connection rate. 70%. Updated quarterly.
C	Landline Compiled	Compiled Phone. Contains approximately 600 million residential listings and 55 million business listings compiled from historical Bell operating company listings and various marketing data sources. Estimated connection rate: 50%. Updated occasionally.
M	Mobile	Mobile Phone. Contains approximately 181 million residential mobile phone listings. Estimated connection rate: 50%. Updated quarterly.
E	Enhanced Mobile	Enhanced Mobile Phone: Contains approximately 2.3 billion current and historical listings from marketing and skip tracing sources. Estimated connection rate: 65%. Updated frequently.
L	Enhanced Landline	Enhanced Landline Phone: Contains approximately 2.3 billion current and historical listings from marketing and skip tracing sources. Estimated connection rate: 65%. Updated frequently.